CO2電子還元過程における酸化/酸化水素由来銅電極における強化されたC2の選択性の起源を調査する
Qiong Lei1, Hui Zhu1, Kepeng Song1
1Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
Journal of the American Chemical Society
|February 12, 2020
まとめ
酸化物/酸化水素で作られた銅の電極は,CO2の削減におけるC2+製品の選択性を高めます. この強化された選択性は,特定の銅酸化状態ではなく,断片化されたナノサイズの銅粒と暴露された高インデックスの側面から生じる.
科学分野:
- 電気化学
- 材料科学
- カタリシス
背景:
- 酸化物/酸化水素で作られた銅電極は,電気触媒によるCO2削減において,C2+製品に対する高い選択性を示しています.
- この選択性の強化の根本的な理由は十分に理解されず,議論が続いている.
研究 の 目的:
- 電気触媒によるCO2還元反応 (CO2RR) で銅の酸化状態と電極構造の役割を調査する.
- オキシード/水酸化物由来銅電極における強化されたC2+選択性の起源を解明する.
主な方法:
- 混合酸化状態 (HQ-CuとAN-Cu) の2種類の銅電極の製造
- 標本抽出のための焦点離子ビーム (FIB).
- 銅の種分布と進化を分析するための電子顕微鏡 (EM) と電子エネルギー損失光譜 (EELS).
- 前処理された電極による制御実験.
主要な成果:
- すべての銅電極は,初期状態に関係なく,CO2RRの間にCu0に還元されます.
- Cu0に完全に還元された処理済み電極は,さらに高いC2+選択性を示した.
- オキシード/ヒドロキシード結晶は,負のポテンシャル下でナノサイズの不規則なCu粒に断片化されます.
- 断片化により粒子の境界が形成され,高インデックスの側面が露出し,C-C結合が容易になりました.
結論:
- 強化されたC2+選択性は,特定の銅酸化状態によるものではなく,むしろ電極の構造的進化によるものである.
- オキシード/ヒドロキシード前駆物質のナノ粒子の断片化と高インデックスファセットの曝露は,改善されたC-Cカップリングの鍵です.
- CO2RR中の電極の振る舞いに関する詳細な洞察を提供している.
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